WARNING: Do not continue reading unless you want all the dirty details of tonight's episode of Pretty Little Liars. Spoilers ahead.

First, let's talk about Ali (Sasha Pieterse). Last week's episode really piqued our suspicion of the queen B. Now we have confirmation. So much for turning over a new leaf — the mean girl still has the mean. Lots of it. She puts on this act tonight of trying to win the school over and make amends for her past mistakes, but after a confrontation with Mona (Janel Parrish), which ends with the two girls slapping one another, we're pretty sure she's far from changed. Forget the slap, Ali has the nerve to refer to Mona as "loser Mona," and tell her, "I'm back, and I'm staying. So get used to it." We probably would have hit her too. We hate to say we're jumping on the Mona train, but we just might have bought a ticket.

Then there are all the hookups. The main attraction: Ezra (Ian Harding) and Aria (Lucy Hale) sleep together, though we're far from discrediting Ali and Emily (Shay Mitchell), who get cozy with some kissing in Emily's bed. Ali tells Emily that she was the hardest to leave but, at this point in the game, we just think it's another line. After Mona outs Ali to the school with a video recording of Ali slapping her, Emily agrees. We're all for not trusting Ali at this point.

In other news, we're happy to report Caleb (Tyler Blackburn) has returned. And thus begins Hanna's mindset: Travis who? Though we wish we could say Caleb's returned in all his glory, he's really deflated tonight. The events in Ravenswood have really bummed him out, it appears. He and Hanna (Ashley Benson) are both struggling with identity crises by all outward appearances. Maybe they can recover together? Because right now they're really depressing us. All they want to do is drink beer and mope.

Jenna is in the same sad boat. She's back in Rosewood after hearing about Shana's death, but appears to be too consumed with grief to search for the identity of the killer just yet. Aria reaches out to her, in her guilt, and Jenna eventually takes her up on the tea and venting offer. The two of them bonding gives us deja vu from seasons past when Aria previously tried to reach out to Jenna all the way back in Season 2. Maybe this time the friendship will actually stick? Wishful thinking. Aria did, after all, kill Shana.

We guessed that Jenna and Caleb wouldn't be the only returning cast members and we were right. No, it wasn't Noel Kahn. It wasn't CeCe. It was A.

We were positive from the get go that Shana wasn't actually Uber-A. That always seemed pretty obvious. But the show didn't slack on giving us an A reemergence worthy of the uber-baddy.

We felt pretty satisfied when we learned at the end of the episode the girl in Ali's grave was named Bethany Young. She was a patient at Radley, who authorities assumed had run away. But the show was far from stopping there. Just as the liars and their posse (aka the boys: Ezra, Caleb and Toby) gathered around the television to hear the new information in the case, a huge explosion shattered the windows. This twist caught us by surprise.

Toby's house, along with a few cars, were charred and/or still up in flames when the group made their way outside. No word yet on how the crash happened and why, but the scene quickly cut to a hooded figure with black gloves unpacking boxes. Oh, and all the girls' phones begin beeping as if signaling an incoming text message.

Welcome back, A. We can't say we've missed you.

What did you think about the 100th episode? Are you surprised A returned?